Low Back Pain

Introduction

The vertebrae in your lower back are larger than in any other part of your spine. Vertebrae are the series of bones that align to form your spine. The spinal section in your lower back is called the lumbar spine. The vertebrae are bigger in the lumber spine because they must support the weight of your upper body. They also withstand powerful forces from the lower back muscles. These strong muscles are attached to the lumbar vertebrae and are used during lifting, bending, and twisting activities.

Low back pain is very common. Muscle, ligament, nerve, and spine injuries are frequent causes of low back pain. Poor posture during movements and “wear and tear” can also cause low back pain. Degenerative diseases, such as arthritis, can cause the spinal structures to break down and put pressure on the spinal cord or nerves. Nerve pressure in the lumbar spine can cause symptoms to spread to the buttocks, legs, and feet. This is because the nerves that exit the spinal cord at the lumbar spine travel to these areas.

A medical examination is necessary to identify the cause of low back pain in order to determine the appropriate course of treatment. The majority of people with low back pain find relief with non-surgical treatments. However, for a small number of people with low back pain, symptoms progress or persist, and surgery can be an effective treatment.

Anatomy

The lumbar spine is located in your lower back.  It curve below your waist. The lumbar spine connects your upper body-- your head, trunk, and arms, to your lower body--your pelvis and legs. Strong ligaments and muscles connect to your spinal column. They provide back stability and movement. The lumbar spine primarily allows you to bend forward or flex and extend or straighten at the waist. You use lumbar flexion when you bend forward to touch your toes. You use lumbar extension when you straighten your back to stand erect after bending forward.

Five large vertebrae make up the lumbar area of your spine. The back part of the vertebra arches to form the lamina. The lamina creates a roof-like cover over the back opening in each vertebra. The opening in the center of each vertebra forms the spinal canal. Your spinal cord and spinal nerves travel through the protective spinal canal. The spinal nerves extend from your lower back, through your buttock, legs, and down to your feet.

Your spinal cord and spinal nerves at the lumbar spine level send signals for sensation and movement between your brain and lower body muscles. Your spinal cord tapers near the first lumbar vertebra and forms a group of nerves called the cauda equina. The cauda equina is involved with regulating bowel and bladder functions.

Six intervertebral discs are located between the vertebrae in your lumbar spine. The discs are made up of strong connective tissue. Their tough outer layer is called the annulus fibrosus. Their gel-like center is called the nucleus pulposus. The discs and two small spinal facet joints connect one vertebra to the next. The discs and joints allow movement and provide stability. The discs also act as a shock-absorbing cushion to protect the lumbar vertebrae.

Causes

Low back pain is caused by abnormalities in the soft tissues, nerves, discs, or vertebrae of the lumbar spine. The soft tissues--muscles, tendons, and ligaments, can strain from over exertion, poor posture, lifting activities, physical stress, and injury. Soft tissue injuries can cause painful muscle spasms or tightening of the lower back muscles.

Compressed, pinched, or irritated spinal nerves can cause symptoms that extend from the low back, through the buttocks and legs, and down to the feet. This commonly occurs from structural changes in the spine. Bone spurs, abnormal bone overgrowths caused by Osteoarthritis, can grow in to the spinal canal or nerve root openings on the vertebrae. Bone spurs and some degenerative diseases can also contribute to a condition in which the spinal canal is narrowed, called Spinal Stenosis. Some degenerative diseases cause the spinal structures to thicken and extend into the spinal canal over time. The narrowed canal causes pressure on the spinal cord and nerves.

If the sciatic nerve is compressed or inflamed, a painful condition called Sciatica can result. The sciatic nerve extends from your lower back down to your foot. Trauma, spinal conditions, or medical conditions that irritate the sciatic nerve cause Sciatica. If the spinal nerves in the lower end of the lumbar spine are compressed, a condition called Cauda Equina Syndrome may result. Cauda Equina Syndrome can cause the loss of bladder and bowel control, along with leg pain, sensory deficits, and weakness.

Changes in the intervertebral discs can also cause low back pain. As we age, our discs lose water content. They become shorter and less flexible, a condition called Degenerative Disc Disease. Once the discs are injured, they do not have the blood supply to repair themselves and they deteriorate. Osteoarthritis and Rheumatoid Arthritis also cause the discs and vertebrae to deteriorate. Normally, the discs act as a cushion between the vertebrae. Without the disc cushioning effect, pain can occur. Without the protective disc, the spine can become structurally unstable and unable to tolerate stress. Degenerative Disc disease can also lead to a herniated disc.

A herniated disc occurs when the outer disc layer, the annulus, ruptures. When the inner content, the nucleus pulposus, comes out of the disc, it can cause pressure on the nerve tissue. When the inner contents of the disc come in contact with the spinal nerves, a chemical reaction occurs that causes irritation and swelling.

Some conditions can directly affect the integrity of the vertebrae. Osteoporosis is a medical condition that causes more bone calcium to be absorbed than is replaced. It contributes to vertebral fractures and deterioration. Spondylolisthesis is a condition that results when a weakened vertebrae slips out of alignment. Another condition, Spondylosis, results when Osteoarthritis or a fracture causes disc degeneration and the overgrowth of bone. Spondylosis causes stiff and painful joints.

Symptoms

The type of symptoms that you experience depends on the cause of your low back pain. Your pain may spread to your buttocks, legs, and feet. Your back may feel stiff, and you may not be able to completely move it. Your hips, legs, and feet may feel weak. You may also have numbness or tingling in your legs, feet, or toes. If you experience a loss of bowel or bladder control, you should seek medical attention immediately. A list of common causes of spinal related lower back pain and a description of symptoms is listed below.

Degenerative Disc Disease may or may not cause symptoms. If you have symptoms, you may feel various types of pain in your back. You may experience sudden pain after an injury or your pain may start gradually and increase over time. Your pain may be so intense that it interferes with your daily activities. You may feel burning pain, pressure, numbness, or tingling. Sitting may make your symptoms increase, whereas lying down may help to relieve pain. Pain is a common symptom of a herniated lumbar disc. You may experience a shooting pain that extends from your buttocks through the back of one leg. Your leg or buttock may feel weak, numb, or have a tingling sensation.

Spinal Stenosis may or may not produce symptoms. If you have symptoms, you may feel pain or numbness in your lower back. Your legs may cramp. They may feel weak, numb, or painful. Your symptoms may come and go. They may vary in intensity. Prolonged standing or walking may cause your symptoms to increase. If you bend forward or sit, your symptoms may be relieved. These positions increase the room in the spinal canal and take pressure off of the spinal cord.

Pressure on the spinal cord or spinal nerves can cause symptoms that radiate to your feet. Symptoms of Sciatica include shooting pain, tingling, weakness, and numbness that may travel from the lower back, through the back of one leg, and into your foot. You may feel burning pain, tingling, weakness, or numbness in your calf, foot, or toes. The weakness may be so bad that you cannot move your foot, bend or extend your knee, or walk. You may have difficulty moving from a seated position to standing up because of shooting pain. Additionally, your pain may become worse when you sneeze, laugh, cough, bend backwards, or have a bowel movement.

Cauda Equina Syndrome can cause the loss of bladder and bowel control. Other symptoms of Cauda Equina Syndrome include low back pain, leg pain, leg weakness, lower body sensory deficits, and reduced or absent leg reflexes. If you experience these types of symptoms, you should seek medical attention immediately.

Diagnosis

Your doctor can determine the cause of your low back pain. The cause must be identified in order to treat your symptoms appropriately. Your doctor will perform a physical examination. Your doctor will ask you about your symptoms and medical history. You will be asked to perform simple back and leg movements to help your doctor assess your muscle strength, joint motion, and joint stability. Your doctor will test the reflexes and sensation in your legs. Your doctor may order lab studies to rule out diseases or conditions that can cause low back pain but are unrelated to the spine.

Your doctor may order imaging studies to identify the location and source of your low back pain. Your doctor will order X-rays to see the condition of the vertebrae in your lumbar spine and to identify fractures, misalignment, narrowed discs, or thickened facet joints. A Flexion and Extension X-ray can determine if there is instability between your vertebrae. For a Flexion and Extension X-ray, you will lean as far forward and then as far backward as you can. Sometimes doctors inject dye into the spinal column to enhance the X-ray images in a procedure called a myelogram. A myelogram can indicate if there are pinched nerves, herniated discs, bone spurs, or tumors.

A bone scan may be used to show fractures, tumors, infections, or arthritis. A bone scan requires that you receive a small harmless injection of a radioactive substance several hours before your test. The substance collects in your bones in areas where the vertebrae are breaking down or repairing bone.

Your doctor may also order Computed Tomography (CT) scans, a Discogram, or Magnetic Resonance Imaging (MRI) scans to get a better view of your spinal structures. CT scans provide a view in layers, like the slices that make up a loaf of bread. The CT scan shows the shape and size of your spinal canal and the structures in and around it. A CT scan is useful for determining which disc is damaged. Your doctor may inject dye into the disc area to enhance the CT images in a procedure called a Discogram. A Discogram provides a view of the internal structure of a disc and can help to identify if it is a source of pain. The MRI scan is very sensitive. It provides the most detailed images of the discs, ligaments, spinal cord, nerve roots, or tumors. X-rays, myelograms, bone scans, CT scans, and MRI scans are painless procedures and simply require that you remain motionless while a camera takes the pictures.

Nerve conduction studies reveal how the lumbar spinal nerves are working. Doctors commonly use a Nerve Conduction Velocity (NCV) test. During the study, your spinal nerve is stimulated in one place and the amount of time it takes for the message or impulse to travel to a second place is measured. The place where the impulse travels slowly at is where the nerve is compressed. Your doctor will place sticky patches with electrodes on your skin that covers the spinal nerve. The NCV test may feel uncomfortable, but only during the time that the test is conducted.

An Electromyography (EMG) test is often done at the same time as the NCV test. An EMG measures the impulses in muscles to identify atrophy or decay. Healthy muscles need impulses to perform movements. Your doctor will place fine needles through your skin and into the muscles that the spinal nerve controls. Your doctor will be able to determine the amount of impulses conducted when you contract your muscles. The EMG may be uncomfortable, and your muscles may remain a bit sore following the test.

Treatment

Surgery

Recovery

Prevention